It's a tiny little grey thing, separate to the circuit board. You might find it in the plastic rectangle at the top of the other half of the fob. Memory doesn't help me at the moment cos I did it a while ago.
If you really can't find it I'll split my other(spare) key and find it for you. But in the original key, there are only two things you can remove and you need both of them,

unless you want to keep and use the original, cut, key to turn the igniton, then leave the transducer in that and put the circuit board in your new fob. But you WILL find that the immobiliser will come back on if you leave too long between getting in the car after opening the door and starting the car.
 
First of all thank you so much for your help, I know I come across thick!

Definitely only a circuit board in mine, nothing else

Is the transducer maybe on a different models key?

All I'm struggling with now is how to get the blade out!!!
 

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Can see the rectangle bit you're talking about the transducer maybe being in, but nothing there!
 

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Millertime_9 said:
Can see the rectangle bit you're talking about the transducer maybe being in, but nothing there!
Click to expand...
Right!
Now, the previous stupid owner may have taken the transducer out, in fact if it is not there the chances are absolutely that this is what he has done. Then he will have taped it somewhere near the ignition switch on the column.
Go have a look for it! Then the immobiliser will still work if you do as I said with the fob, although I am a bit concerned as it seems as if you have a "one button" fob and mine has two buttons, one for lock one for unlock.
Get back to me, pm if nec
Stan
 
Stanleysteamer said:
Right!
Now, the previous stupid owner may have taken the transducer out, in fact if it is not there the chances are absolutely that this is what he has done. Then he will have taped it somewhere near the ignition switch on the column.
Go have a look for it! Then the immobiliser will still work if you do as I said with the fob, although I am a bit concerned as it seems as if you have a "one button" fob and mine has two buttons, one for lock one for unlock.
Get back to me, pm if nec
Stan
Click to expand...
Haha maybe that's why I couldnt find it if the plonker has removed it

Take it this thing must be taped somewhere or my car wouldn't start?

Nah I have 2 buttons, whether they both do anything however..!!
 

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Right!
When you push either of the two buttons the little red light on the fob should light up, even if you have to do this with the tip of another key or some other small object. You can also look at the flashing immobiliser light on the dash, that should come on or go off as you do the above.
Second, the transducer HAS to be near the ignition switch or it won't pick up the signal, so start right next to it and look all around it, he may have stuck it behind a panel, to one of the column panels, in amongst some wiring, he obviously wanted to hide it. But it MUST be there otherwise you couldn't immobilise or de-immobilise the car! Look in the plastic that goes absolutely around the ignition switch it IS tiny. You may just see a bit of tape with a lump in it!
 
Right, all, after a fascinating time playing with keys and PMing OP I have found out that a circuitboard from within the key fob can still be used to immobilise and de-immobilise the car, but if the car re-immobilises after the normal time which seems to be about 20 seconds, then with just the metal key, separate from the circuit board, you can only start the car if you de-immobilise it again with the button on the circuitboard. BUT, if the circuitboard is in the fob with the key, you do not have to do that. You just turn the key.
So, anyone out there, despite the fact that the metal part of the key touches nothing on the circuitboard as far as I can tell, how in heck is this the case?
 
Now, the previous stupid owner may have taken the transducer out,
Click to expand...
Would be good to know what's about before missleading people. The D2 fob does not have a "transducer" separately from the circuit board, that's a Freelander or Rover 75 thing which have the same shape fob. The D2 has all the ''hardware" on the circuit , that little square thing on the left side wiewable in the pic from post 22 is a ''resonator'' which works with the remobilisation coil so the circuit looks OK, The Freelander/ Rover fobs(which are often sold as for D2) dont have that crystal, they have a transponder in the casing which is useless and an unlock command is needed for the passive immobiliser if the vehicle is not started in 30 seconds after it was unlocked... from the picture from post 22 the circuit looks OK so as long as the fob works if the microswitch is pressed just a new casing is needed.
 
sierrafery said:
Would be good to know what's about before missleading people. The D2 fob does not have a "transducer" separately from the circuit board, that's a Freelander or Rover 75 thing which have the same shape fob. The D2 has all the ''hardware" on the circuit , that little square thing on the left side wiewable in the pic from post 22 is a ''resonator'' which works with the remobilisation coil so the circuit looks OK, The Freelander/ Rover fobs(which are often sold as for D2) dont have that crystal, they have a transponder in the casing which is useless and an unlock command is needed for the passive immobiliser if the vehicle is not started in 30 seconds after it was unlocked... from the picture from post 22 the circuit looks OK so as long as the fob works if the microswitch is pressed just a new casing is needed.
Click to expand...
Right.
Stanleysteamer said:
It's a tiny little grey thing, separate to the circuit board. You might find it in the plastic rectangle at the top of the other half of the fob. Memory doesn't help me at the moment cos I did it a while ago.
If you really can't find it I'll split my other(spare) key and find it for you. But in the original key, there are only two things you can remove and you need both of them,

unless you want to keep and use the original, cut, key to turn the igniton, then leave the transducer in that and put the circuit board in your new fob. But you WILL find that the immobiliser will come back on if you leave too long between getting in the car after opening the door and starting the car.
Click to expand...
What is in red is wrong, what is in green is right and I fully accept this.
I was only trying to help the OP who has since pmed me and now his key is working fine.
I know my knowledge of electricals is weak but I also know what I have done that works. I passed this knowledge on. In my pm conversation I worked out what you said and that there was no separate transponder in the key. This I and OP agreed on and now he can immoilise, de-immobilise and start his car.

What I still don't understand is why the resonator in the fob works to deimmobilise the car after the time lapse has immobilised it, when you turn the key, but it DOESN'T work, when the resonator is in the other fob, on the same key ring, but the key in the ignition is exactly that, just a key.
Incidentally thanks for eventually jumping in and making me look a fool again. Although I did manage to sort OP out to his and my satisfaction.
Looking forward to the answer to my last question from you who knows more about electrics in your little finger than I do in my whole head.
 
Last edited:
But in the original key, there are only two things you can remove and you need both of them,
Click to expand...
In the original fob there is only one thing to remove and that's the circuit board... in this particular situation an unlock command with the original fob is needed and if that doesnt work then EKA code... simple as that
 
For future reference:
Rover 75 / Freelander fob with transponder
Rover 75 fob.jpg


D2 fob, (the pointed bit is instead of the transponder encircled above where this is missing)

Fob difference.jpg
 
sierrafery said:
In the original fob there is only one thing to remove and that's the circuit board... in this particular situation an unlock command with the original fob is needed and if that doesnt work then EKA code... simple as that
Click to expand...
And if you read my last post you'd see I agreed with you, as I do on ALL electrical things!

You ARE the guru on all things electrical and you know I recognise that.
But I would like an answer as to the difference in deimmobilising then starting with the circuitboard in the starting keyfob as opposed to right next to it on the keyring.
 
Yes, as long as the fob is close enough to the passive remobilisation coil(which is around the ignition barrel) the vehicle should start once it was unlocked and the alarm disabled but this has not much to do with this problem where the alarm is triggered cos the passive immobiliser kicks in when the alarm is disarmed. Here an unlock command is needed to stop the alarm, or EKA code
 
Ok
I'm not going to bang on about this much more but here is the scenario I have.
Buttons on fobcase wore out so got new fob case.
Transferred circuitboard in fob to new fobcase so plastic buttons now work
Didn't cut new key.
I open the car with the button on the new fob/case, get it put old key in ignition.
if I turn key within the time limit the car starts.
If I DON'T turn the key before the immobiliser light starts flashing then although all the other lights on the dash light up, the starter will not kick in.
So, I repress the unlock button on the new fobcase and then the car will start.

With my old key, it doesn't matter how long I leave it between unlocking the car and putting the key in the ignition, the key will start the car. NO NEED to repress the unlock button.

Both me and the OP found this out and can now start our vehicles.

Any ideas why there is a difference between the circuitboard actually being in the fob with the starting key and it's being right next to it, i.e. on the same keyring?
You mentioned alarms. This is not an issue, the alarm never sounds in either scenario.
 
Stanleysteamer said:
You mentioned alarms. This is not an issue, the alarm never sounds in either scenario.
Click to expand...
Before this long discussion about the passive immobiliser started i replied to the OP's post 17 where the problem was the alarm https://www.landyzone.co.uk/land-rover/td5-disco-2-wouldnt-start.351014/#post-4669891
then the whole ''transponder" discussion started which has nothing to do with post 17.
Stanleysteamer said:
Any ideas why there is a difference between the circuitboard actually being in the fob with the starting key and it's being right next to it, i.e. on the same keyring?
Click to expand...
I dont really understand your dillema cos i'm a bit confused about your "new fob" and "old fob" thing... all i can say for sure is that if a well working D2 FOB is near the ignition the passive immobiliser should be no factor, the key blade has no involvment in this, the common thing is that many owners bought Rover 75 keys sold as D2 keys by some schmucks on ebay and those are working only to unlock the vehicle/disable the alarm they dont work with the passive remobilisation coil, the unlock command disables the passive immobiliser too for few seconds so the vehicle can be started with any key immediately after the vehicle was unlocked but once the passive immobiliser kicked in if the fob is not for D2 or if it has some problem with the resonator another unlock is needed provided that everything works well with another fob... if there is only one fob available and no well working D2 fob to double check it's possible to be some problem on the pasive coil's circuit as well.

i hope that it's clarified now cos i can't explain better.
 
The OP's original problem has been solved because he can now start and drive his car away.
I gave him a rough workaround which works for both him and me.
All of us eventually have the problem of the flexible plastic on the key fob breaking leaving the microswitches exposed.
We can all get new fob covers from the bay or whatever.
We can all get new keys cut.
Whether getting new keys cut quickly or not is an issue for the individual owner of the vehicle with the problem.
The ideal is to put the circuit board in the new fob cover and get the key blank cut to match the original key.
But in a non-ideal situation, in the meantime before getting the key blank cut, the workaround of putting the circuitboard in the new fob cover, and using the buttons on that while continuing to use the original key with its empty fob to start the car is an option. As long as you know what to do once the car drops into immobilised mode, which you agree takes about 30 seconds.
(There is no mention of Rover 75 fobs or keys or anything else to do with the wrong keys and fobs. Neither myself nor the OP mentioned it.)
I have yet to take the circuit board out of one of my keys and determine exactly how close to the ignition switch it has to be held before the ignition key can be turned and the car started without having to push the "unlock" button on the fob with the circuit board in. I am just surprised that having the new fob cover with the original circuit board in it on the same keyring as the key that will start the car, is not enough to do it and this for one simple reason.

On the D1, (yes this is a new element to my thinking), this is exactly how it works. You have a key and a separate fob, as long as the fob is on the ring, the car starts when you turn the key. I expected this to work on the D2. But it doesn't, unless you start the car within the first 30 secs after unlocking the car.

I expect you are now going to tell me why this is. There must be a difference between the system on the D1 and on the D2.

Now do you get where I am coming from?
Sorry if I didn't mention this before.
 
Stanleysteamer said:
(There is no mention of Rover 75 fobs or keys or anything else to do with the wrong keys and fobs. Neither myself nor the OP mentioned it.)
Click to expand...
I mentioned the rover fob cos you insisted with the ''transducer'' thing which is specific for rover not for D2
Stanleysteamer said:
On the D1, (yes this is a new element to my thinking), this is exactly how it works. You have a key and a separate fob, as long as the fob is on the ring, the car starts when you turn the key. I expected this to work on the D2. But it doesn't, unless you start the car within the first 30 secs after unlocking the car.

I expect you are now going to tell me why this is. There must be a difference between the system on the D1 and on the D2.
Click to expand...
i think i've already explained that but i say again: (there is a huge difference between D1 and D2 but from this point of view it's the same), if the D2 fob is within the passive coil's range) e.g. on the ring it should work exactly like when it's attached to the blade... if you need to unlock after 30 seconds to start then it's a rover fob or a faulty D2 fob which has a problem with the ''resonator'' circuit or a passive remobilisation coil circuit problem, i can't be more explicit on this with my poor english

the gist is mentioned in the description of the item here too(read it all): https://www.island-4x4.co.uk/igniti...ck-discovery-9804-britpart-d2lock-p-2495.html
 
Ok, so my key, with the cicuitboard in the fob, works as all keys should. It starts no matter how long between unlocking and starting.
My other key, with the circuit board in another fob cover, but on the same ring, only starts after 30 seconds if I press the unlock button again.
This is the same as OP's.
So, coincidentally it looks as if we have the same or similar problems, but with the same temporary solution.
As one of my keys works but the other doesn't I am now thinking that the problem lies with one of the circuit boards. Is this the resonator, as I am assuming the passive coil is around the ignition switch?
I could, although I'd rather not, take the circuitboard back out of its new fob and put it back in the fob with the key that starts the car and see if it behaves as it does in the new fob cover.
Thanks for clarifying that the metal part of the key has nothing to do with this.
This is all both very interesting and boring at the same time. Does that make sense to you?
 
Incidentally I have tried holding the fob and key combination that works properly right next to the ignition while turning the key which is only a key, and that definitely doesn't work which seems weird bearing in mind what you just wrote. It was much closer than just being on the same ring.
 
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